Hemophagocytic Histiocytic Sarcoma Case Study: Forrest

A 11 yr old Golden with hemophagocytic histiocytic sarcoma, 38 months in remission. FidoCure® identified a rare tumor suppressor mutation and suggested additional therapy that may have helped target tumor cells.


Forrest, a 11-year old Golden Retriever, first presented to The Veterinary Care Center in  Norwalk, CT with poor appetite and lethargy. Unfortunately, an abdominal ultrasound revealed a mass on the spleen. A splenectomy was performed and the splenic tumor was diagnosed as hemophagocytic histiocytic sarcoma, a cancer with very poor prognosis.

Forrest was one of the first patients whose clinical management leveraged FidoCure™ assessment (Feb. 2018). Our DNA diagnostic testing identified a mutation in an important tumor suppressor gene, the ataxia–telangiectasia mutated (ATM) serine/threonine kinase. ATM is an enzyme that kick-starts DNA repair following damage.

After surgery, the veterinarian opted for an approach that included follow-on treatment with both lomustine (CCNU) and a targeted therapy histone-deacetylase (HDAC) inhibitor. Both can damage tumor cell DNA. With at least one altered copy of ATM, any tumor cells remaining in this canine patient after surgery would be faced with both a combination of these DNA damaging agents and further reduced ability to repair the DNA damage, enhancing cancer cell death. In theory, this is a potent anti-cancer approach for this patient.

The role of FidoCure™ is to provide information regarding options. The tumor genome information that FidoCure™ provided was effective in this regard, and Forrest is still healthy over a year later. The goal of The One Health Company is to bring these options to all canine cancer patients.